1. Field of the Invention
The present invention is related to a new artificial grain leather which enables the easy application of textured crimps, the leather having a feeling of high quality in creases, a high bond strength between the coating and the base fabric, and not a paper-like touch, but a softness with a feeling of fullness like natural leather. Furthermore, the present invention is related to a new artificial grain leather which offers excellent air permeability, moisture vapor transmission, and water repellency, in addition to the above-mentioned features.
2. Description of the Prior Art
A large number of artificial grain leathers in which the base material and the coating are bonded together have been proposed in the past. Furthermore, the market demand for fabrics with softness and flexibility has been strong in recent years. Although realization of a soft texture alone can be simply achieved with conventional technology, softness and strength are in an inversely proportional relationship, and the problem was what artificial grain leather would first satisfy these antinomic properties at a practical price. Furthermore, the attainment of a sense of high quality in creases and the easy crimping and wrinkling of fabrics are also inversely proportional to softness. No product which offers all the qualities of these properties integrated with normal physical properties at a level enabling practical use is known.
Further, there are no products which sufficiently and simultaneously offer both air permeability and moisture vapor transmission. When requirements for a high quality appearance and texture are also considered, there are even fewer products which offer satisfaction.
Methods for providing an artificial grain leather with air permeability and moisture vapor transmission include the following: formation of pores with a foaming agent; formation of pores by addition of a water soluble material and then extracting this material; surface finishing of the fabric with a porous film obtained through a wet coagulation technique.
In each of these methods, the pores are distributed randomly. When many large pores are formed to satisfy the need for both air permeability and moisture vapor transmission, these same pores become the weak point of the artificial grain leather; they weaken the grain surface strength, repeated tensile strength, and repeated shear strength, and impair the surface luster and color tones.